High-density automated storage and retrieval system

ABSTRACT

A high-density storage system for goods is described in which totes carrying the goods are stored in a storage structure and stored and retrieved via stationary or mobile conveyers running along opposite ends of each layer of the storage structure. The totes may be moved to or from the conveyers as the rows move at a constant velocity toward or away from the conveyers. Totes at the ends of rows are quickly moved and stored in another row until the desired tote appears at the end of the row, at which point the desired tote is carried to an exit point of the storage structure by one of the conveyers.

RELATED APPLICATIONS

This application is a national phase filing under 35 U.S.C. § 371claiming the benefit of and priority to International Patent ApplicationNo. PCT/US2020/067174, filed Dec. 28, 2020, which is acontinuation-in-part of PCT Application PCT/US2020/033790, filed at theU.S. Receiving Office on May 20, 2020, which claims the benefit of U.S.Provisional Patent Application No. 62/850,191, filed May 20, 2019. Thecontents of these applications are incorporated herein in theirentireties.

BACKGROUND

Companies are pushing to maximize the storage density and efficiency ofautomated storage and retrieval systems (AS/RS) in their orderfulfillment process. AS/RS systems use automated carriers that typicallymove either between or on top of structures that hold products or totesfilled with products. In the case of systems (Schaefer iCube, Cuby, andMiliload Crane, Dematic Multishuttle, Venderlande ADAPTO, and OPEXPerfect Pick) where carriers move in between aisles of products and/ortotes, there is a limit as to how dense the system can be in that thespace required for the carrier movement reduces the overall potentialstorage density of the system.

Some systems (Autostore, and CimCorp) maximize density by stackingproducts or totes vertically, which maximizes storage density, but haspotentially lower efficiency when retrieving products or totes that areburied lower in the stacks. In the case of the CimCorp system, a gantryservices a range of totes that are stacked on the floor, which assiststo minimize infrastructure but ultimately has a limit on performancebased on a limited number of gantry arms overlapping the same workspace.The Autostore system stacks totes vertically within a raised structure.Retrieval robots have to lift the totes from the top one-by-one. Thisresults in a limit on performance to retrieve totes that are lower inthe stack with each lift taking a longer amount of time proportional tothe height of the tote stack or product being lifted.

SUMMARY OF THE INVENTION

The embodiments described herein provide the capability for a highlydense storage solution while also providing a high level of performance,thereby improving both density and speed of retrieval over prior artsystems. Instead of stacking the totes vertically (which has an inherentheight limit due to the mechanical limit and the weight of the totes),the totes are arranged in horizontal rows within a supporting structure.Unlike other systems, the totes are mechanically coupled to allow for arow of horizontally connected totes to be pulled and/or push together asa unit by pulling or pushing the tote on the end of a row, which willalso pull or push all other totes within that same row that areconnected to each other. This arrangement allows any totes within a rowto be retrieved by repeatedly pulling and decoupling the outer tote ortotes from the row until the right tote is retrieved. It also allows forthe easy storage of totes. A tote could be stored in this AS/RS systemsimply by pushing a tote into a row that has an empty spot. As that toteis pushed into that row, it will automatically couple itselflongitudinally when it comes into contact with the totes that arealready in that row. This efficient storage approach could also be usedto store the outer totes that were removed from a row to access the totethat needs to be retrieved.

The described embodiments store totes within a layered supportstructure. This structure supports the weight of all totes as well asproviding rows within the structure in which totes can be stored. Thetotes are placed into the structure rows through a horizontal motion ina similar manner to other rack-based storage solutions. The novelstorage structure allows for a high number of totes to be stored in asingle row, whereas more standard rack structures allow for only a smallnumber of totes or packages to be stored on a given shelf, because thereis no efficient way to access totes that are located deep in the row.The described embodiments are able to retrieve totes from anywherewithin a row upon request with a high level of performance in comparisonto other high-density storage solutions. This is possible since alltotes, no matter how deep they are located in the row, could be accessedjust by pulling on the outside totes until the totes of interest are atthe edge of the row. Pulling on the outer tote or totes will also pullall the other totes that are coupled, allowing the tote that needs to beretrieved to be pulled outside of the row.

One embodiment of the invention retrieves totes within the system whenthey are pulled or pushed to the end of a row, where the tote isdecoupled when moved in a direction other than the direction of thelongitudinal axis of the row. In preferred embodiments, the tote isautomatically decoupled when moved in a direction perpendicular to thelongitudinal axis of the row. This exposes the next tote in the row tobe pulled or pushed and decoupled. This process can then be repeateduntil the target tote to be retrieved is pulled or pushed to the end ofthe row and decoupled. The totes that were removed and decoupled fromthe row previous to access the target tote can be moved to another rowone or more at a time. Those totes can then be coupled onto totes thatwere previously in the new row as they are push/pulled into the row.

The novel tote coupling embodiment also provides a method for totes tobe coupled to one another through linear motion in the couplingdirection. As totes are pushed into one another, features on the totescouple to one another to allow for transfer of forces between the totesalong the length of the row. In one embodiment, coupling can only beaccomplished in the direction of the row, whereas decoupling can onlyoccur in any direction other than a direction along the longitudinalaxis of the row. In other embodiments, active coupling and decouplingmechanisms may be provided.

There are multiple embodiments of how totes can be stored within thesupport structure. One embodiment has totes arranged in rows that aresingle tote height and coupled together along the length of the row.Other embodiments have totes arranged in stacks that are two or moretotes high with one or more of the totes in the stack being coupled tothe next tote stack in the row. For this embodiment, it is possible thatneighboring stacks of totes in a row have different number of totes intheir stack, resulting in one or more totes being coupled to the nexttote stack in the row.

There are multiple embodiments for the novel technology wherein one ormore automated carriers can access the totes in the support structure.One embodiment of the novel technology has one or more automated roboticcarriers that moves in the center of multiple rows (on the left andright) of totes. It can pull or push totes from a row on either side toeither retrieve it for delivery or push it into another row on eitherside until the target tote is retrieved.

Another embodiment for the novel technology features one or morecarriers that travel along the outside of one or more faces of thestorage structure along the ends of the tote rows. In this embodiment,automated carriers can push or pull totes from a row, decouple them fromthat row, and move it to another row or retrieve the tote from a singleside of the carrier. Having the carrier on the outsides face(s) of thestructure allow for a high density of storage space while still allowingfor access to the automated carrier components from outside of thestorage structure for maintenance or other operations.

A further embodiment of the novel system has carriers working in two ormore pairs on opposite sides of the structure, with both automatedcarriers of each pair aligned on opposite ends of the same rows, orcapable of storing and retrieving totes from the same or nearby rows.This embodiment utilizes both automated carriers to push and/or pulltotes from both ends of the rows. The automated carriers would be ableto move totes from one row to another in unison with one another untilthe tote(s) that need to be retrieved are removed from the storagestructure row and decoupled from neighboring totes in the row, providinga “circular” motion of the totes within the rows. In some embodiments,during these push and pull motions, the motion of the totes could bekept at a constant velocity even during decoupling and coupling, therebyminimizing the time needed for the actions.

This novel process is capable of having higher performance than othersolutions for multiple reasons. First, by having totes within a rowcoupled to one another, the automated carriers only have to act on thetotes on the end or near the end of the row, to move all of the coupledtotes within that row. Secondly, by having totes that can decouplethrough motions in direction different from the direction of thelongitudinal axis of the row, the process is able to be efficient andquick, reducing storage and retrieval times. Third, as totes are movedto decouple from one row, they can be coupled to a new row in the samemotion. Once the tote is coupled to the new row, it can be pushed orpulled resulting in the movement of the entire row. Finally, bymaintaining the constant velocity of the totes as they are being pushedand pulled, the time needed to retrieve a certain tote or to store atote can be minimized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows several views of a first embodiment of a tote where thetote comprises an integral carrier.

FIG. 2 shows and inside views of the tote of FIG. 1 , showing thecoupling mechanism.

FIG. 3 shows several views of a second embodiment of a tote where thetote comprises a flat carrier upon which containers or boxes containinggoods may be stacked.

FIG. 4 shows the passive end-to-end coupling process for totes.

FIG. 5 shows several views of one embodiment of an active decouplingprocess utilizing an eccentric roller.

FIG. 6 shows totes being coupled by longitudinal motion by being pushedonto a row.

FIG. 7 shows totes being decoupled by moving in a directionperpendicular to the row and re-coupled to an adjacent row based on theperpendicular motion.

FIG. 8 shows a tote coupling/decoupling in a vertical perpendiculardirection.

FIG. 9 shows a tote being coupled/decoupled in a horizontalperpendicular direction.

FIG. 10 shows the coupling and decoupling of tote stacks stored within arow.

FIG. 11 shows a first embodiment of a storage structure for totes.

FIG. 12 shows a single layer of the first embodiment of the storagestructure shown in FIG. 11 .

FIG. 13 shows the positioning of carriers on the exterior of the storagestructure of FIG. 11 .

FIG. 14 shows a second embodiment of a storage structure for totes.

FIG. 15 shows the positioning of carriers on the exterior of the storagestructure of FIG. 14 .

FIG. 16 shows an input/output mechanism for use with the storagestructure of FIG. 14 .

FIG. 17 shows one embodiment of a carrier for use with the storagestructure of FIG. 11 .

FIG. 18 shows a support structure for supporting the carriers shown inFIG. 17 for use with the storage structure FIG. 11 .

FIG. 19 shows one embodiment of the carrier for use with the storagestructure of FIG. 14 .

FIG. 20 shows a support structure for supporting the carrier shown inFIG. 19 for use with the storage structure of FIG. 14 .

FIG. 21 is a detailed view of a portion of the support structure shownin FIG. 20 .

FIG. 22 shows a first embodiment of the push/pull mechanism for pushingand pulling rows of totes within the storage structures of FIG. 11 orFIG. 14 .

FIG. 23 shows a second embodiment of the push/pull mechanism for pushingand pulling rows of totes within the storage structures of FIG. 11 orFIG. 14 .

FIG. 24 shows the process of pushing and pulling totes to move totesfrom one row to another.

FIG. 25 shows the output portion of the input/output mechanism for usewith the storage structure of FIG. 11 .

FIG. 26 shows the input portion of the input/output mechanism for usewith the storage structure of FIG. 11 .

FIG. 27 shows the output portion of the input/output mechanism for usewith the storage structure of FIG. 14 .

FIG. 28 shows the input portion of the input/type of mechanism for usewith the storage structure of FIG. 14 .

FIG. 29 shows a perspective view of a tote holding structure.

FIG. 30 shows a structure configuration having tandem carriers movingalong the outside of the rows.

FIG. 31 shows the circular movement of totes between adjacent rows toaccess totes located on row interiors.

FIG. 32 is a schematic example of the retrieval of a tote from theinterior of a row.

FIG. 33 is a diagrammatic view of the process for storing and retrievingtotes.

FIG. 34 shows two adjacent rows in a layer showing the movement of totesfrom one row to another to retrieve a tote in the middle of a row.

FIG. 35 shows an optimization of the process for retrieving totes.

FIG. 36 (A-D) are graphs showing the velocity and acceleration of rowsand the efficiencies experienced by earlier described embodiments of theinvention (A-B) and by improved efficiency embodiments of the invention(C-D). The graphs show that the time required to push or pull 8 totes“To” is much shorter than the time T required using discrete push andpull motion.

FIG. 37 shows an improved-efficiency embodiment of the invention whichutilizes conveyers along the ends of each row and which allows totes tobe decoupled from and coupled to rows while the rows are moving at aconstant velocity.

FIG. 38 is a top schematic view of a portion of a layer of the storagestructure showing the circular motion enabled by the use of theconveyers along the side of the layers of the storage structure.

FIG. 39 (A-M) are a series of schematic diagrams showing the steps toretrieve a tote from the interior of a row of the storage structureusing the embodiment having the conveyers along the sides of the layerand wherein the totes exhibit a “circular” motion.

FIG. 40 is a schematic diagram of a layer of the storage structureshowing limitations of the improved-efficiency embodiment.

FIG. 41 is a schematic top view of a portion of the storage structureshowing the steps to retrieve a tote from the interior of a row of thestorage structure using the embodiment having conveyers along the sidesof the layer and wherein the totes exhibit a “serpentine” motion.

FIG. 42 (A-C) are a series of schematic depictions showing the steps toretrieve a tote from the interior of a row of the storage structureusing an alternate embodiment of the invention having mobile conveyersalong the sides of the layer.

FIG. 43 (A-H) show various embodiments of a drive mechanisms for movingthe rows of totes.

FIG. 44 (A-J) shows a sequence of operations wherein the tote motion isgravity-assisted by moving totes from an upper row to a lower row.

FIG. 45 shows one embodiment of a software architecture of a controlsystem for the described system.

FIG. 46 shows an alternate embodiment of a software architecture of acontrol system for the described system.

DEFINITIONS

As used herein, the term “carrier” refers to a locally or remotelycontrolled robotic or mechanism capable of moving about a tote supportand storage structure in a vertical, horizontal or both directions andcapable of accepting, carrying and discharging one or more totes.

As used herein, a “tote” refers to a device capable of carrying goodsfor transport by a carrier from one location to another. The tote may beconfigured to be manipulated by a carrier for purposes of movement froma storage location to and from an exit or entry point of the storagesystem. The tote may be configured as a container or as a flat structureon which other containers may be placed.

As used herein, the term “storage structure” refers to a structure forstoring totes and facilitating the placement and retrieval of toteswithin the storage structure by a carrier.

As used herein, the term “layer” refers to multiple rows for the storageand retrieval of totes. Layers can be oriented in a horizontal,vertical, or any orientation within the storage structure.

As used herein, a “row” is defined as a portion of a storage structurecapable of storing a plurality of totes aligned longitudinally with eachother and able to move in the longitudinal direction of the row. A rowmay be horizontal, vertical, or any orientation within the storagestructure, but horizontal orientation is the preferred embodiment,because the force to pull a row of totes in the horizontal direction issignificantly less than the force needed to lift the coupled totes invertical direction.

As used herein, the term “constant velocity”, with respect to themovement of rows of totes, is defined as the movement of a row at asubstantially constant speed after being accelerated from a stoppedposition or before being decelerated to a stopped position.

As used herein, the term “conveyer”, is defined as any system capable ofmoving objects from one place to another, as, for example, using belts,rollers or any other means. A conveyer could operate independently froma mobile carrier or as part of the mobile carrier. A mobile carriercould be considered a conveyer.

DETAILED DESCRIPTION

The embodiments described herein utilize multiple carriers that work inunison to manipulate totes or other stored product from a storagestructure, to efficiently retrieve a particular tote or store a tote.The process utilizes a system of totes or carriers that allow for forceto be shared between a row of totes in a singular linear direction (ineither positive or negative direction) but also allows for the totes tobe decoupled mechanically by using electromechanical actuator, or bymoving them in a direction other than the direction of the longitudinalaxis of the row (either positive or negative direction). The noveltechnology can manipulate the totes or other products in both directionsto move a target tote (and as a result, all totes coupled to the targettote) toward an end of the row where it may be decoupled from the row.

Tote Configuration

One aspect of the invention is directed to various configurations oftotes for storage in a storage structure. A first embodiment of the toteis shown in FIG. 1(A) wherein the tote embodies a container structure100 for accepting goods for storage. In an alternate embodiment of theinvention, the tote may be configured as shown in FIG. 3(A) as a flatplatform having the coupling and mobility components and which canaccept goods or containers for goods stacked thereon, as shown in FIG.3(B).

The totes are required to be able to be moved back and forth in adirection along the longitudinal axis of any row in the storagestructure such that they may be manipulated as rows of totes within thestorage structure. In one embodiment, shown in FIG. 1(B), tote 100 maybe configured with wheels or casters 102 which slide along rails 104disposed in the storage structure. In an alternate embodiment, tote 100may be configured with angled wheels 104 which slide along rails 106 asshown in FIG. 1(C). In yet other embodiments, not shown in the figures,tote 100 may be configured with low friction sliding surfaces whichengage mating surfaces in the storage structure. The mobility componentsof the embodiments shown in FIG. 1 (B,C) may be fitted to the types oftote shown in FIG. 1(A) or FIG. 3(A). Wheels or casters 102 may bedisposed on any portion of the tote and are not limited to the placementshown in FIG. 1(A).

A second aspect of the invention is directed to a coupling system whichallows totes to be coupled end-to-end as they are pushed into eachother, thereafter allowing an entire row of coupled totes to be pushedor pulled from the tote on the end of the row. In one embodiment of theinvention, totes may be configured with an interface to a drivemechanism for moving the coupled totes into and out of the rows of thestorage structure.

One embodiment of this aspect of the invention is shown in FIG. 2(A),showing a side view of tote 100 in which one side on the end of the toteis configured with a hook, while the opposite side is configured with ahook receptacle for accepting the hook of an adjacent tote. FIG. 4 (A-D)show one embodiment of the coupling process, in which the totes 100 arepushed together and wherein hook 400 on a first tote, having a slantedsurface, is pushed upwardly by the lip of the hook receptacle 402 on theadjacent tote. In the embodiment shown in FIG. 4(C), entire tote israised to allow hook 400 to slide into hook receptacle 402. In analternate embodiment, hook 402 may be spring-loaded such as to be ableto be raised for disposal into the hook receptacle 402 without raisingthe entire tote 100. FIG. 4(D) shows tote 100 in a fully coupledposition. Other embodiments of the coupling mechanism are contemplatedto be within the scope of the invention.

The de-coupling of the totes may occur in one of two ways. In a firstembodiment, the totes are decoupled as they are moved in a directionother than the direction of the longitudinal axis of the row, allowinghook 400 to slide out of the side of hook receptacle 402. As shown inFIG. 1(A) and FIG. 2(A), hook receptacle 402 is open on the ends such asto allow hook 400 to slide out of hook receptacle 402 in response to aperpendicular motion of the totes with respect to each other.

In a second embodiment of the invention, the totes may be decoupledeither by an active or passive mechanism. FIG. 5 (A-D) show an exampleof an active decoupling mechanism in which an eccentric roller isprovided to lift tote 100, and thereby lift hook 400 out of hookreceptacle 402. Note that when eccentric roller 500 is on the tote 100having the hook 400, as shown in FIG. 5(B), tote 100 must be raised todecouple the totes, while if eccentric roller 500 is on the tote 100having the hook receptacle 402, as shown in FIG. 5(D), tote 100 must belowered to decouple the totes. FIG. 5(C) shows eccentric roller 500 inneutral position to allow for passive coupling of the totes. Otherdecoupling mechanisms are contemplated to be within the scope of theinvention.

FIG. 6 shows how totes are coupled as they are inserted into rows of thestorage structure. FIG. 6(A) shows the situation wherein a gap 604 ispresent at the end of the row into which tote 600 is being pushed. Whentote 600 is pushed into row 602, it will couple with tote 606, fillingempty spot 604, however, none of the totes 606, 608, 610, in row 602will be pushed in the longitudinal direction. FIG. 6(B) shows thesituation wherein tote 606 is present at the end of row 602. In thiscase, when tote 600 is pushed into row 602, it will immediately couplewith tote 606 and will cause totes 606, 608, 610 to be pushed into row602 as tote 606 is pushed into row 602. In both cases, the end result isshown in FIG. 6(C) in which totes 600, 606, 608, 610 are present in row602. Thereafter, as shown in FIG. 6(C), if tote 600 is pulled, it wouldalso pull on totes 606, 608 and 610 that are coupled to it in row 602.Likewise, pushing on the tote 600 would move the entire row of connectedtotes in the opposite longitudinal direction.

As the totes are coupled at the end of the row, and then inserted into aparticular row, the coupled totes could fill in a gap within that row.If the tote farthest into the row crosses this gap and encountersanother tote that is already in the row, the pushing motion by thecarrier will cause them to couple and they will now move as a coupledunit.

FIG. 7 shows the motion required for passive decoupling of the totes.FIG. 7(A) shows tote 700 currently at the end of row n. Row n is pulledin the direction of the arrow by a carrier (not shown) to bring tote 700onto the carrier. FIG. 7(B) shows the shifting of tote 700 in adirection perpendicular to the row by the carrier, which causes apassive decoupling of tote 700 from tote 701 in row n. As shown in FIG.7(C), Tote 700 is immediately passively coupled, as a result of theperpendicular motion, to adjacent tote 702 in row n+1. In alternateembodiments, if, for example, tote 702 were not at the end of row n+1,tote 700 could simply be pushed into row n+1 and would couple with thefirst tote at the end of the row by virtue of its longitudinal motionwithin the row. In yet another embodiment, after tote 700 has beendecoupled from row n as shown in FIG. 7(B), it may be removed by acarrier to an exit point of the system.

Totes can be coupled such that they can be decoupled in any directionother than longitudinal axis of the row (e.g., vertically, horizontally,diagonally). FIG. 8 shows a distinct embodiment where totes can bedecoupled/coupled in a vertical perpendicular direction, while FIG. 9shows an alternative embodiment wherein totes can be decoupled/coupledin a horizontal perpendicular direction. Totes could also be decoupledby disabling the coupling mechanism using an electromechanical actuator.

The novel technology for tote connections are not limited to a singletote in a row. The concept can be extended to embodiments whereinmultiple totes are stacked on top of each other within the row, shown inFIG. 10 . The stacks, which can be comprised of at least one tote heightor width, retain the ability to be coupled in the direction of the row.As one or more of the totes on the end stack are pulled, all tote stacksin the row move as well. As the totes are moved along the perpendiculardirection and are clear of all totes in the previous row, they aredecoupled.

Storage Structure Configurations

A second aspect of the invention involves the storage structure in whichthe totes are stored. The present invention provides two basicconfigurations for the storage structure.

In a first, preferred, embodiment of the invention, referred to hereinas the “single-layer bot” embodiment, a layered storage structureconcept, shown in FIG. 11 is used. In this configuration, the storagestructure comprises multiple layers, as shown in FIG. 12 , of connectedtotes. Note that while FIG. 12 shows a single layer as being completelyfull of totes, it is possible that, in operation, a single gap of anysize may be found within any row of totes. In this embodiment of theinvention, a carrier support structure is utilized at one end or bothends of each row to support one or more robotic carriers capable ofmanipulating a row of totes to store and retrieve a target tote.

In the single-layer bot embodiment, the carriers are restricted tomoving only within layer of the support structure which they service(their “home” layer), as shown in FIG. 13 (although, in a variation ofthis embodiment, the single-layer bots may be moved between layers by aconveyer). Theoretically, the single-layer bot embodiment may operatewith one bot per layer on one side of the storage structure, or one pairof robots per layer, with one bot of each pair disposed in the samelayer on opposite sides of the storage structure, such as to be able toinsert and remove totes from opposite sides of the structure. Morerealistically, multiple robots per layer may be provided for moreefficient operation. In this configuration, the robots may only movewithin their home layer. Note that, while FIGS. 11 and 13 show thelayers stacked horizontally, it is contemplated that the layers may alsobe stacked vertically. But at the minimum, only a single robotic carrieris needed to pull on the outer tote or totes to access any tote within arow.

Because the carriers are restricted to movement only within their homelayer, the single-layer bot embodiment of the storage structure alsorequires a vertical input/output conveyer located at one or both ends ofthe structure, which allows movement of the totes from the layer fromwhich they were retrieved down to the input/output conveyer, and toraise incoming totes from the input/output conveyer to the level thelayer where they will be stored. The input/output conveyer is discussedin more detail below.

A second embodiment of the storage structure is shown in FIG. 14 and isreferred to herein as a “multi-layer bot” embodiment. In thisembodiment, the carriers are able to move both vertically andhorizontally, as shown in FIG. 15 . Multi-layer bot carriers cantherefore retrieve totes from any row in any layer or from theinput/output system and deliver the totes to any row in any layer, or tothe input/output system.

In this embodiment, the input/output system may consist of a pair ofconveyers running longitudinally through the middle of the supportstructure as shown in both FIGS. 14 and 15 . Other configurations of theinput/output system may also be used with this embodiment. Detail of theinput/output system is shown in FIG. 16 and will be discussed in moredetail below.

Carrier Configurations

The carrier configurations for use with the single-layer bot andmulti-layer bot storage structures are described in this section.

FIG. 17 shows a first embodiment of a carrier 1700 for use with thesingle-layer bot storage structure. Carrier 1700 is capable of movingback and forth in the longitudinal direction driven by drive wheels 1710and supported by idler wheels 1706. The carrier shown in FIG. 17 iscapable of servicing two rows of its home layer at a time. That is, afirst tote can be pulled from a first row simultaneously with a secondtote being pushed into a second row. Push/pull actuators 1704 arecapable of pulling an entire roll of totes from the layered bot storagestructure such that the first tote in the row rests in a first positionon conveyer roller 1712. The tote may then be shifted to a secondposition using conveyer rollers 1712 where may be pushed into a secondrow by push/pull actuators 1704.

Note that, in this embodiment, the movement of the tote from the firstto the second position via conveyer rollers 1712 on carrier 1700 enablesthe passive decoupling of the tote from the row from which it wasretrieved. As the tote is then pushed into its destination row, the toteis passively coupled to the first tote in the destination row if thereis a tote at the end of the row. If there is a gap in the destinationrow, totes may continue to be pushed into the destination row until thegap is closed and all totes in the destination row have been passivelycoupled via their longitudinal motion causing contact of the couplingmechanisms of the totes.

In a second embodiment, carrier 1700 may also be configured withde-latch rollers 1702, as described above with respect to FIG. 5 , todecouple the tote from its row.

Note that, while FIG. 17 shows carrier 1700 capable of handling twototes simultaneously, the invention is not meant to be limited thereby.Carriers may be configured with any number of places for acceptingtotes, including embodiments having a single place, in which case thecarrier must move to place the tote in its destination row.Theoretically, carrier 1700 could be configured with a number of placesequal to the number of rows in its home layer. In such embodiments,drive wheels 1710 and idler wheels 1706 would become superfluous as thecarrier would not move within its home layer.

FIG. 18 shows the interaction of carrier 1700 with the single-layer botversion of the storage structure 1802 and the outboard frame structure1806. Carrier support structure 1806 includes tracks 1808 along whichcarrier 1700 will roll or slide to access the rows of its home layer.Note that, in this configuration, there are two outboard carrier supportstructures 1806, one positioned as shown on one end of the storagestructure 1802 and a second one positioned on the opposite side of thestorage structure 1802.

FIG. 19 shows a second embodiment of carrier 1900 for use with themulti-layer bot configuration of the storage structure. In thisembodiment, the carrier 1900 can move both vertically and horizontallywith the carrier support structure 2002 shown in FIG. 20 . FIG. 19 showsthe mechanism allowing the two-dimensional movement of carrier 1900which includes roller pinion 1910 which will engage with racks disposedon the support frame structure. The roller pinions 1910 are driven by anX-axis or horizontal drive 1906 and Z-axis or vertical drive 1908.Carrier 1900 may also include steering assembly 1904 and retractablerollers 1902 for interaction with the carrier support structure 2002.

FIG. 20 shows carrier 1900 in place on carrier support structure 2002servicing storage structure 2004. FIG. 21 shows detail of the carriersupport structure 2002 showing toothed racks (both vertical andhorizontal) for accepting vertical and horizontal pinions 1910.

FIG. 22 shows a first embodiment of a push/pull mechanism for pulling arow of connected totes from the storage structure such that the firsttote in the row is positioned on the conveyer of the carrier, and forpushing a tote already on the carrier into a destination row. FIG. 22shows the use of telescoping actuators 2200 for use as a push/pullmechanism. Telescoping actuators 2200 would be configured with a hook onone end capable of interacting with the coupling mechanism on the totes.Actuators 2200 could be any type of actuator, for example, pneumatic,hydraulic, electric, etc.

FIG. 23 shows a preferred embodiment of the push/pull mechanism, shownin perspective view in FIG. 23(A) and a side view in FIG. 23(B). To pullon a tote, linear actuator 2314 pushes pull bar platform 2310 towardsthe tote with the pull bar 2302 raised. Pull bar 2302 is brought intoposition and is dropped into place by latch actuator 2304. The linearactuator 2314 then reverses and pulls the tote onto the carrier whilelatch actuator 2304 holds the pull bar 2302 down in the locked position.Aligning multiple pull bars allows a tote to be shifted along thecarrier. To insert the tote into a different row, linear actuator 2314is actuated to push against the tote with push bumper 2306 with the pullbar 2302 in the unlocked position.

Note that, although the push/pull mechanisms shown in FIGS. 22 and 23are shown in use with the multi-layer bot version of the carrier, eitherconfiguration may be used with the single-layer bot version of thecarrier shown in FIG. 17 as well. Also, it should be noted that, inalternate embodiments, carriers may be fitted with only a pushcapability or only a pull capability.

FIG. 24 shows the carrier actuation motion. In FIG. 24(A), the actuatorsare retracted upon arrival at the designated rows within the storagestructure. FIG. 24(B) shows the extension of actuator A grabbing thetote at the end of the row. FIG. 24(C) shows the retraction of actuatorA, which pulls the tote onto the carrier (and moves all the connectedtotes in the row towards the carrier). FIG. 24(D) shows the conveyershifting the tote to the adjacent row. Note that the perpendicularmovement of the tote with respect to its row passively decouples it fromits row and may automatically couple it to the next row. Alternatively,the tote may be automatically coupled to the next row when pushed ontothe row by actuator B. FIG. 24(E) shows both actuators A & B extended.Actuator A grabs the next tote while actuator B pushes the previous toteinto the adjacent row. FIG. 24(F) shows retraction of both actuators A &B, which pulls the next tote from onto the carrier. FIG. 24(G) shows atote being decoupled from its row using the latch rollers 1712 shown inFIG. 17 .

Input/Output Mechanisms

In addition to retrieval, storing and shuffling of totes, the systemmust be capable of outputting a tote from the system and intaking a toteto the system. In both embodiments of the storage structure this isaccomplished via an input/output mechanism.

FIG. 11 shows the input/output mechanism for the single-layer botconfiguration of the storage structure. Totes are delivered to and fromthe input/output mechanism via a conveyer. Note that, in certainembodiments of the invention the input/output mechanism may be locatedon both sides of the storage structure, while in other embodiments, theinput/output mechanism may only be located on one side of the storagestructure. In yet other embodiments, one or more input/output mechanismsmay be located at any convenient location in proximity to the storagestructure, including, for example, on the interior of the storagestructure, underneath the storage structure or on top of the storagestructure.

FIG. 25 shows one possible embodiment of a process for outputting totesfrom the storage structure. In this embodiment, carriers 1700 convey aretrieved tote to the output buffer ramps 2504. The ramps are slopedsuch that the totes, once placed on the ends of the ramps nearest thecarriers 1700 will roll or slide down the ramp 2502. A mechanism (notshown) may be provided to stop the downward motion of the tote until anopen spot on vertical conveyer 2502 arrives at the bottom of the ramp,at which time the mechanism will allow the tote to continue its downwardmotion onto vertical conveyer 2502. Vertical conveyer 2502 rotates witha circular motion and, when the retrieved tote reaches the bottom of thevertical conveyer 2502, it is pushed onto the conveyer shown in FIG. 11.

FIG. 26 shows one possible embodiment of a process for inputting totesinto the storage structure. In this embodiment, totes arrive at thebottom of vertical conveyer 2502 via the horizontal conveyer shown inFIG. 11 . When a spot is available on vertical conveyer 2502, the toteis pushed onto the conveyer and raised to a level slightly higher thanthe level of its destination layer. The tote is then pushed onto aninput buffer ramp 2602 and rolls or slides passively down the ramp. Amechanism (not shown) may be provided to stop the downward motion of thetote until carrier 1700 arrives at the bottom of the ramp, at which timethe mechanism will allow the tote to continue its downward motion ontocarrier 1700. Carrier 1700 then proceeds to place the tote in theappropriate row within its home layer.

FIG. 27 shows one possible embodiment of a mechanism for outputtingtotes from the storage structure in the multi-layer bot configuration.In this embodiment, the multi-layer bot configuration, the bottom tworows of the storage structure may be reserved for input and outputbuffers. The output buffers consist of alternating rows on each side ofthe structure. The inset of FIG. 27 shows a side view of the mechanism.Totes are retrieved from their source layers by the two-dimensionalcarriers 1900 and are transported vertically to an output buffer locatedon one end of the storage structure. The tote is pushed off of carrier1900 onto a downward facing ramp 1600, as shown in the inset of FIG. 27and in FIG. 16 , where it rolls or slides downward. A mechanism (notshown) may be provided to stop the downward motion of the tote until anopen spot on conveyer 1604 arrives at the bottom of the ramp, at whichtime the mechanism will allow the tote to continue its downward motiononto conveyer 1604. Conveyer 1604, then transports the tote to the endof the structure where it is pushed onto a horizontal conveyer as shownin FIG. 11 .

One possible embodiment of an input process for the multi-layer botconfiguration is shown in FIG. 28 . In this embodiment, totes aredelivered to conveyer 1604 via the horizontal conveyer shown in FIG. 11. Conveyer 1604 delivers the tote to an input buffer located in thefirst row of the storage structure. The tote is then pushed onto adownward facing ramp 1602, as shown in the inset of FIG. 28 and in FIG.16 and rolls or slides down the ramp. A mechanism (not shown) may beprovided to stop the downward motion of the tote until a two-dimensionalcarrier 1900 arrives at the bottom of the ramp, at which time themechanism will allow the tote to continue its downward motion ontocarrier 1900 on the outside of the storage structure. Thetwo-dimensional carrier 1900 picks up the tote and transports itvertically to its destination layer, and horizontally to its destinationrow. Totes may roll or slide down the ramps passively, or they may beassisted by actuators.

Storage and Retrieval Schemes

The carriers described herein are able to move along the outside face orfaces of the storage structure to target row locations to be able toservice rows within a limited range or along the whole face of thestorage structure. Such a storage structure is shown in FIG. 29 in amultilayer configuration.

In an embodiment of the single-layer bot configuration, shown in FIG. 30, the carriers work in pairs along the opposite sides of the supportstructure. The movement of the robotic systems to manipulate the totesis shown in the top view of the support structure shown in FIG. 31 . Thecarriers are able to remove a tote from its source row by decoupling thetote by moving it in a perpendicular horizontal direction to its row andcoupling it to an adjacent row in the same motion. Alternatively, asdiscussed above, the tote may be decoupled from its source row by thepassive roller mechanism shown in FIG. 5 . The rows are then pushed inopposite directions by the carriers on opposite sides of the storagestructure, with the totes at the ends of the rows being uncoupled by therespective carriers and placed into the adjacent row until the desiredtote appears at the end of one of the row. The pushing and pulling ofadjacent rows may be bidirectional, depending on which end of a row thetarget tote is closest. Note that, if a row is fully occupied by totes,it is not necessary that a first carrier pull the row while the secondcarrier pushes the row.

An operational example is shown in FIG. 32 . In FIG. 32(A), tote number5 is the target tote which is nested in the middle of a two-row pair oftotes, denoted as row n and row n+1. Note that there is a gap in bothrow n and row n+1. In FIG. 32(B), a pair of carriers, shown as a leftcarrier on the left side of the rows and a right carrier on the rightside of the rows, is moved to a row containing the target tote as wellas an adjacent row. Note that the carriers could also have moved to bepositioned on the ends of row n and n−1 (not shown). In FIG. 32(C), theleft carrier pulls the totes from row n and the right carrier pullstotes from row n+1 to make space for more totes in that row. It shouldbe noted that the right carrier would only need to begin removal oftotes from row n+1 after the gap between tote G and tote H has beenclosed and tote G and tote H are coupled together. In FIG. 32(D), theleft carrier pushes totes from row n into row n+1, while the rightcarrier pushes totes from row n+1 into row n until the desired tote(tote 5) is captured by the left carrier. The process could also work inreverse order wherein the totes in row n are pushed to the right, whiletotes and row n+1 our pushed to the left until the right carriercaptures tote 5. In FIG. 32(E), the left carrier pushes tote 4 into rown+1 such that tote 5 is the only tote left on the carrier and, in FIG.32(F), the left carrier moves to deliver the tote to the exit point ofthe system as soon as all other totes are clear. The right carrier maybe moved to the next retrieval location. It is not necessary that theleft carrier and the right carrier are members of a fixed pair ofcarriers but may be paired with other carriers as is convenient tooptimize storage and retrieval. Note that the described storage andretrieval scheme is useful in both the single-layer bot and multi-layerbot configurations of the storage structure.

The carrier described herein could work individually or in pairs onopposite faces of the structure. When operating on opposite faces of thestructures, multiple carriers would work in tandem to push/pull coupledtotes linearly along their storage row, and in the perpendiculardirection to decouple them from their row, and either place them inanother row and push/pull them into that row or retrieve that tote fordelivery to the exit point of the system.

FIG. 33 is a schematic diagram showing a process for the storage andretrieval of totes. The process utilizes both a retrieval queue 3302 oftotes waiting to be retrieved and a storage queue 3303 of totes waitingto be stored. To begin the process, tote is removed from retrieval queue3302 and, at 3304, the process retrieves the location of the tote. Thelocation of all totes is stored in the database and each locationcomprises a layer, a row within the layer and a depth within the row.The retrieval process starts at 3306 and, at 3308, the carrier moves tothe row containing the tote to be retrieved. The detail of the toteretrieval process is shown in box 3310. The carrier pulls the rowcontaining the desired tote from the storage structure and shifts thefirst tote in the row, which is now on the carrier, to the adjacent row.The carrier then again pulls the row containing the desired tote, whilesimultaneously pushing the tote on the carrier into the adjacent row.This process of is repeated until the desired tote is on the carrier, atwhich point the desired carrier must be decoupled from its row either byactive decoupling or by passive decoupling brought about by the carriershifting the tote perpendicularly with respect to its row, as discussedabove. At this point, any other tote on the carrier may be pushed intothe adjacent row in the layer, and the carrier will proceed to the exitpoint of the storage system. In the case of the single-layer botconfiguration, the tote will proceed to the end of its home layer, wherethe desired tote will be pushed onto the ramp leading to the verticalconveyer 2502. In the case of the multi-layer bot configuration, thetote will be transported to the bottom of the storage structure wherethe tote will be pushed onto the ramp leading to the internal conveyer1604, as discussed above.

It should be noted that the process may require a carrier on theopposite side of the storage structure acting in tandem with the carrierretrieving the desired tote. As totes are removed from the rowcontaining the desired tote they are shifted to an adjacent row, wherethey are pushed in and thereby coupled to the adjacent row. If theadjacent row is full, a tote will be pushed out into the opposite sideof the storage structure. In this case, a second carrier must be thereto retrieve that tote, shift the tote the adjacent row (the rowcontaining the desired tote) and push it into the row. In someembodiments, an electrical or mechanical stop may be provided at the endof the row to prevent a tote from being pushed out of the row until acarrier is present to receive it. The carrier may de-activate the stop,thereby allowing the tote to be pushed out of the row and received bythe carrier.

It may not be necessary for the two carriers to arrive at positions onthe structure wherein they act in tandem at the same time. For example,if the adjacent row into which totes are pushed after they are retrievedfrom the row containing the desired tote is not completely full, a totewill not be pushed out of the storage structure on the opposite sideuntil any gap within the row is filled. Therefore, the second carriermay be occupied with other tasks until it is necessary for it to be atthe required position to catch totes which are being pushed out of theadjacent row.

Returning to FIG. 33 , at 3312 the carrier moves to the drop off pointand delivers the retrieved totes to the input/output mechanism. At thispoint the carrier is able to retrieve a tote from the input/outputmechanism to store within the storage structure. The first tote to bestored is removed from queue 3303 and is assigned a storage location at3305. Again, the storage location must consist of a layer, a row withinthe layer, and the depth within the row where the tote will be stored.It should be noted that, in most cases, the tote will be stored at theend of a row. At 3316, the carrier moves to the required location andthe tote is pushed into the assigned row. At 3318, the next tote isremoved from the retrieval queue and the process repeats.

FIG. 34 shows the process of moving a desired tote from the middle ofthe row to the end of the row where the carrier may pick it up. FIG.34(A) shows the desired tote as being at a depth of five within the row.At FIG. 34(B), the carriers pull on the ends of the rows, therebyretrieving a tote from opposite sides of the storage structure. In FIG.34(C), the end tote on each row and shifted to the side, which passivelydecouples it from its row and, in FIG. 34(D), the shifted totes arepushed into and coupled with the adjacent rows. In alternateembodiments, only the row containing the desired tote may be pulled and,when the tote is shifted to the adjacent row and pushed into the row, atote on the opposite side of the row may be pushed out of the storagestructure onto the carrier. As such, it may not be necessary for thesecond carrier on the opposite side of the structure to pull on the row;the second carrier may passively receive totes which are pushed out ofthe row by the first carrier. The desired tote is now moved one totecloser to the end of the row and the process is repeated until thedesired tote is located on the carrier, at which point it is decouplefrom its row and carried to the exit point of the system.

Retrieval Optimizations

There are several optimizations possible which make the storage andretrieval process more efficient. FIG. 35 shows one such optimization.This process defines the direction in which carriers retrieve totes.With carriers on both sides of the storage structure, totes, could bepulled to either carrier for retrieval. The optimized algorithmminimizes the number of push/pull cycles required to move a tote to acarrier. In FIG. 35(A), which shows a top view of a horizontal layer ofrows, the target tote is closer to the top carrier than the bottomcarrier and, as such, top carrier will pull the row and will be able toretrieve the tote using seven pull/shift cycles. FIG. 35(B) shows asimilar case however, there is a gap in the row between the desired totein the top carrier. As such, even though the desired tote is locatedphysically closer to the top carrier, because the top carrier will notbe able to pull the portion of the row containing the desired tote, therow is pulled by the bottom carrier, and will require 13 pull/shiftcycles to move the tote to the bottom carrier, as shown in FIG. 35(C).

Other optimizations are possible. In one embodiment, when a tote isremoved from the storage queue and assigned a storage space, the storagespace can be assigned based on location of the next tote in theretrieval queue. The tote to be assigned can be stored in the sameposition or, alternatively, in the same layer and row as the next toteto be retrieved. When the carriers move to the target row the tote to bestored is pushed into the row while the first tote is pulled. Thisreduces the movement time of the carriers.

In another embodiment, the queues for storage and retrieval of the totesmay be optimized. Instead of retrieving the first tote in the retrievalqueue, the estimated retrieval times for all totes in the queue arecompared and the tote with the lowest estimated retrieval time may beretrieved first. This is repeated for each retrieval process.

In yet another optimization, carriers may be used in parallel. For asingle-layer bot configuration, only one carrier may be used to pick atote so that other carriers are free to pick other totes or stagepicking. This optimization only is useful when the layer is notcompletely full (i.e. there are rows having a gap in them). For themulti-layer bot configuration parallelization will improve the retrievalrate and will reduce the number of required bots to operate the storagefacility.

In a further optimized embodiment, the layout of the totes may beoptimized. The totes may be optimized to stocking retrieval sequence toappropriately “buried” unpopular totes deeper in the row and “expose”popular totes to be closer to the edge of the row. The initial anddesired layout requires keeping more popular totes in parts of thestorage structure that are easy to access, for example, nearer theinput/output mechanisms. The system can reconfigure the layout duringslow times to prepare for busy times by shuffling popular totes to moreeasily accessible spots in the storage structure. Note that thepopularity of totes can be gauged based on number of times a particulartote is retrieved within a predefined recency.

In yet a further optimized embodiment, a predictive layout optimizationmay be used to customize the desired layout to optimize for differentorder popularity based on time of day or week. The layout of the toteswithin the storage structure can be modified to better suit pickers. Thesystem could account for multiple parallel order fulfillment for pickersand may use machine learning to account for pickers efficiency (and itemefficiency) to reduce the amount of required queueing.

Improved Efficiency Embodiments

One difficulty with the embodiments described thus far is that, whilethey are more efficient than existing prior art designs, they are stillnot optimally efficient in terms of time-to-retrieve and powerconsumption. This is illustrated by the graphs in FIG. 36 . Theinefficiency arises from the fact that the movement of the rows must bestopped while each tote on the end of the row is decoupled from the rowand then started back up again to move the next tote in the row to aposition where it can be decoupled. FIG. 36(A) is a graph of thevelocity of the rows as the totes are shifted out of the row. As can beseen, the entire row must come to a complete stop before the tote at theend of the row is decoupled from the row, negatively impacting thetime-to-retrieve. Even worse is the fact that the row must bedecelerated, as shown in FIG. 36(B), to bring it to a complete stopbefore the tote is decoupled, then accelerated again to move the nexttote into position. To decelerate the row, force must be applied to therow to slow its forward momentum. This constant starting and stoppingmotion is inefficient both in terms of the time required to retrieve atote and in terms of the power required to constantly accelerate anddecelerate the rows, which may be significant due to the weight of therows.

FIGS. 36 (C-D) shows graphs similar to those shown in FIGS. 36 (A-B)showing the difference in the row velocity and row acceleration betweenearlier embodiments of the invention and the improved-efficiencyembodiments of the invention. The graphs in FIGS. 36 (C-D) show thatonce the row of totes is accelerated to a desired velocity, the rowstays at that velocity while totes are loaded and unloaded until thelast tote has been added to or removed from the row, at which time therow velocity is slowed to zero. Thus, the “start and stop”inefficiencies shown in embodiments to which FIGS. 36 (A-B) refer areeliminated, thus improving the time-to-retrieve any particular tote.Likewise, the power required to accelerate and decelerate row of totesis only needed at the beginning and end of the movement of a single rowof totes.

The described inefficiencies may be eliminated by having the rows oftotes move at a constant velocity, thereby eliminating the constantstart and stop motion and the need to accelerate and decelerate therows. This requires having the ability to decouple the totes from therows and to couple totes to the rows while the rows are in motion andwithout slowing the rows. Additional embodiments of the inventionproviding this ability and thereby realizing a gain in bothtime-to-retrieve and power consumption will now be described.

A first embodiment providing the improved efficiency described above isillustrated schematically in FIG. 37 . In this embodiment, each level inthe storage structure is provided with a stationary or mobile conveyer3700 disposed on each end of the rows of the layer. In one aspect of theinvention, the conveyers may only move in one direction, with thedirection of the opposing conveyers 3700 being opposite each other asshown in FIG. 37 . In other aspects of the invention, conveyers 3700 maybe free to move in either direction and may be configured dynamically.The presence of conveyers 3700 eliminates the need for mobile carriers3710 to convey totes-of-interest to an exit point of the storagestructure. The mobile carriers 3710 in this embodiment serve to bridgethe rows of totes with the conveyers 3700 and may, in other embodiments,also serve to provide a drive mechanism for moving the rows of totesand/or mechanisms for coupling and decoupling the totes to and from therows. In one aspect of the embodiment, mobile carriers 3710 arehorizontally mobile, being free to move to the end of any row within thelayer of rows. In other aspects of the embodiment, mobile carriers maybe both horizontally and vertically mobile, such as to be able to movehorizontally between rows of the storage structure.

FIG. 38 shows one aspect of the embodiment in which a constant circularmotion is set up between a source row in a destination row within thelayer of rows to retrieve the tote of interest 3802, which is present insource row 3804. Two mobile carriers 3710 are moved to the ends ofsource row 3804. An additional two mobile carriers 3710 are moved to theopposite ends of a destination row, in this case, row 3806 within thelayer of rows. Note that row 3806 may be any row within the layer ofrows but, in preferred embodiments, may be a row in which an additionaltote-of-interest is located or a row in which an incoming tote enteringthe storage system may be stored. Rows 3804 and 3006 are moved at asubstantially constant velocity and without stopping in oppositedirections, as shown in FIG. 38 , until tote of interest 3802 is movedonto conveyer 3700, at which point motion of the conveyer moves thetote-of-interest 3802 to an exit point of the storage system.

It should be noted that, for rows 3804 and 3806 to move at asubstantially constant velocity and without stopping, it is necessarythat totes are able to be decoupled from source rows and coupled todestination rows while the source or destination row moves at a constantvelocity. As such, mobile carriers 3710 may be flared at the endsadjacent to conveyers 3700 to accommodate the side-to-side movement ofthe totes (i.e. movement in the direction of travel of the conveyer3700) while still being moved in the longitudinal direction of the rows(i.e., in a direction perpendicular to the direction of travel of theconveyers 3700). As such, the totes experience a movement in directionsboth parallel to the longitudinal axis of the source of destination rowand perpendicular to the longitudinal axis of the source or destinationrow, such as to move in an approximately circular path as the totepasses through the mobile carrier and onto the conveyer. Note that, toaccommodate the coupling and decoupling of totes to and from the rowswhile the rows are moving at a constant velocity, it may not be possibleto move totes to and from adjacent rows or rows that are less than aspecified number of rows apart from each other, depending on the designof the mobile carriers.

The movement of the totes in a direction perpendicular to thelongitudinal axis of the row may, as in previous embodiments, besufficient to decouple the totes from a source row or to couple thetotes to destination row. An example of such a mechanism is shown inFIG. 2 . However, any means of coupling and decoupling the totes may beused, including, for example active or passive mechanisms located on themobile carrier or the conveyer.

In some embodiments, the conveyers may be equipped with shoes to actuatethe movement of the totes from the conveyers to the rows. Preferably,the shoes would move at the same velocity as the conveyer. It should benoted that any implementation of shoes may be used and, in someembodiments, mechanisms other than shoes may be used to position thetotes on the conveyer and/or actuate the movement of the totes to therows. Furthermore, it is desirable that the conveyers 3700 also move thetotes at the same constant velocity with which the rows are moving toprovide a smooth transition of the totes between the rows and theconveyers.

FIG. 39 provides a step-by-step explanation of the retrieval of atote-of-interest in accordance with a first improved efficiencyembodiment of the invention. FIG. 39(A) shows the storage system in astatic state prior to the retrieval of the tote-of-interest, which isindicated as being tote E6. It should be noted that the mobile carriersare initially in random positions, typically predicated on their endingpositions from the last storage and/or retrieval operation for thislayer. In FIG. 39(B), it can be seen that the mobile carriers have movedinto positions to enable them to retrieve tote-of-interest E6 fromsource row 6. One mobile carrier has moved to each end of the row 6 inwhich tote E6 resides, while one tote has moved to each end of adestination row in this layer of the storage structure, in this case,row 2. As previously noted, the destination row may be any row withinthe storage structure and may preferably be a row having anothertote-of-interest which may be retrieved or a row in which an incomingtote is desired to be stored. Although in preferred embodiments, thelongitudinal motion of the conveyer decouples the totes from the end ofthe row, in some embodiments, mobile carriers may be provided with anactive mechanism (or ramp) that assists in the decoupling of the totesfrom one another when the tote is being moved through the carrier.

FIG. 39(C) shows that the row 6 in which tote E6 is stored has begunmovement to the left and that tote A6 has moved through the mobilecarrier on the end of the row and is being positioned on the leftconveyer. In FIG. 39(D), tote A6 has been decoupled from row 6 and restsagainst shoe 1 on the left conveyer. The movement of tote A6 in thedirection of the left conveyer also serves to decouple tote A6 from row6. It should be noted that, as the tote is being decoupled, it is beingmoved both longitudinally in the direction of movement of row 6 andperpendicular to the longitudinal direction of the movement of row 6 byvirtue of the movement of the left conveyer. This bidirectional movementserves to decouple the tote from row 6 and will serve to couple the toteto its destination row (i.e., row 2).

In FIG. 39(E), it can be seen totes A6, B6 and C6 have been movedagainst shoes 1, 2 and 3 on the left conveyer and, by virtue of themovement of the left conveyer, are moving toward row 2. It should benoted that the tote-of-interest, tote E6, now rests on the mobilecarrier.

In FIG. 39(F), shoe 1 has been activated to push tote A6 onto the mobilecarrier for row 2. Totes B6, C6, and D6 have moved further down theconveyer toward row 2, and the tote-of-interest, E6, is being moved ontothe left conveyer. In some embodiments, the mobile carrier adjacent theleft side of row 2 may be provided with a ramp which allows tote A6 toslide down and into contact with tote A2, thereby becoming coupled withtote A2. In other embodiments, the mobile carrier may be provided with adrive mechanism that moves tote A6 from the left conveyer and intocontact with tote A2 in row 2.

In FIG. 39(G), tote B6 has been moved onto the mobile carrier by virtueof the activation of shoe 2, thereby becoming coupled with tote A6, andtote C6 has been moved toward row 2 by virtue of the activation of shoe3, thereby becoming coupled to tote B6. By virtue of the movement of row2 to the right to accommodate tote A6, tote T2 has been pushed out ofthe end of row 2 and onto the mobile carrier.

In FIG. 39(H), tote D6 has been pushed onto carrier by shoe 4. Themovement of row 2 to the right to accommodate totes B6 and C6 has pushedtotes S2 and R2 out of row 2 and tote T2 has moved on the right conveyeragainst shoe A toward row 2. Tote E6, resting against shoe 5, has movedfurther along the left carrier toward row 2.

FIG. 39(I) shows that shoe 5 has not been activated, thereby allowingtote E6 to move past row 2 and further along the left conveyer toward anexit point of the storage system. Totes T2, S2 and R2 have moved in thedirection of the right conveyer toward row 6 and tote Q2 is being pushedonto the right conveyer. Note the empty spaces at the end of row 6 whichwill accommodate totes T2, S2, R2 and Q2.

FIG. 39(J) shows the movement of tote T2 onto the mobile carrier byvirtue of activation of shoe A. Totes S2, R2 and Q2 have moved furtheralong the right conveyer toward row 6. FIG. 39(K) shows the movement oftotes S2 and R2 towards row 6 by virtue of the activation of shoes B andC, thereby pushing tote T2 further into row 6. FIG. 39(L) shows thefurther movement of totes from row 2 into row 6. It should be noted thattotes T2, S2, R2 and Q2 may be pulled into row 6 by virtue of thepreviously mentioned drive mechanism. In addition to, or in lieu of thedrive mechanism, the mobile carrier adjacent the right side of row 6 maybe provided with a ramp which allows totes pushed onto the mobilecarrier by a shoe to slide down and into contact with a tote at the endof the row.

FIG. 39(M) shows the completed operation with totes T2, S2, R2 and Q2present in row 6, with row 6 containing an empty space created by virtueof the removal of tote E6, from the storage structure.

It should further note be noted that operations involving the storagestructure may be “chained” with each other. That is, one operation neednot be completely finished before starting the next operation. Forexample, in the example just discussed, a new tote may be stored in astorage structure by introducing it via the left conveyer after tote E6(FIG. 39(G)), and then pushing it into row 2 after tote D6 (FIG. 39(H)).In such cases, one additional tote would then move on to the rightconveyer from row 2 and be stored into the empty slot in row 6 caused bythe exit of tote D6 from the system. Other examples can be contemplated.

FIG. 40 shows one possible limitation of the improved efficiencyembodiment of the invention. Because there is only a single belt on eachside of the storage structure, in embodiments where the belts only movein one direction, there may be constraints on the rows towards the edgesof the layer in which the rows can only have tote extracted in a singledirection. The number of rows to which the limitation may apply may be afunction of the space required to set up the “circular” motion of thetotes. As discussed before, the decoupling and coupling of the totes mayrequire mobile carriers to have flared ends and may also requireconcurrent bidirectional movement of the totes in a direction both alongthe longitudinal direction of movement of the row and perpendicular tothe longitudinal direction of movement of the row.

In another aspect of the first improved efficiency embodiment, shown inFIG. 41 , the totes may be moved in a “serpentine” motion from a sourcerow to a destination row as opposed to being moved in a “circular”motion. In FIG. 41(A), mobile carrier 4002 is in a position adjacent row2 and carrier 4004 is in a position adjacent row 6 such as to facilitatethe removal of totes from row and into row 2. However, after the tote ofinterest has been removed from row 6, as shown in FIG. 41(B), mobilecarrier 4004 moves adjacent row 8 and mobile carrier 4002 moves adjacentrow 6 such as to allow the totes that were removed from row 2 (to makeroom for the totes that were formally stored in row 6) and onto theright carrier to be moved into row 8 instead of row 6. The totes thatare subsequently pushed out of the left side of row 8 are moved backinto row 6 via carrier 4002. The serpentine method of movement mayprovide an optimization in the movement of the totes to increaseefficiency. For example, if a second tote-of-interest is located in row8, it may be possible “chain” storage or retrieval operations tominimize the movement of the carriers and to eliminate intermediatestorage steps. One example of chaining events would be the introductionof a new tote into the system, shown as tote 4006 in FIG. 41(B).

It should be noted that, while the invention is discussed in terms ofthe conveyers being equipped with shoes to move totes on a conveyer to amobile carrier, any well-known mechanism of moving an object such as toremove it from a conveyer may be used.

Also be noted that, in one embodiment, the invention may operate withonly one carrier on each side of the layer of rows of totes. In such anembodiment, the mobile carrier would start at a source row and remain atthe source row while one or more totes are moved in the source row ontothe conveyer. The mobile carrier would then move to the destination rowwhile the totes are being moved by the conveyer and would thenfacilitate the movement of the totes from the conveyer to thedestination row.

In a second improved efficiency embodiment, shown in FIG. 42 , thestationary containers located on either side of the layer of rows may beeliminated in favor of mobile carriers having conveyers several rowswide thereon which may be moved from place to place within the layer oneither side of the storage structure.

FIG. 42(A) shows the configuration of the totes as they were in FIG.39(A), in which the tote-of-interest is E6, stored in row 6. Mobileconveyers 4202 and 4204 are located on opposite sides of the layer ofthe storage structure and are horizontally mobile within that layer. Insome embodiments of the invention, mobile conveyers 4202, 4204 haveentry and exit points a fixed number of rows apart (as an example, FIG.42(A) shows the entry and exit points of mobile carriers 4202, 4204being five rows apart), while in other embodiments, the overall size aswell as the location of the entry and exit points may be configurable.In preferred embodiments of the invention, the mobile conveyers areconfigured with a movable belt or other mechanism which moves the totesalong the length of the mobile conveyer. In preferred embodiments of theinvention, the mobile conveyers on each side of a layer may move totesin opposite directions, however, the invention is intended to includeembodiments wherein the mobile conveyers are configured to move totes inthe same direction or are able to be configured to change the directionin which the totes are moved dynamically. Also, in preferred embodimentsof the invention, each layer of the storage structure will be providedwith its own pair of mobile conveyers, however, in other embodiments,mobile conveyers may be vertically mobile such as to move verticallybetween layers. In yet other embodiments of the invention, a singlelayer of the storage structure may be configured with more than onemobile conveyer on either side of the layer.

In the scenario shown in FIG. 42 , mobile conveyers 4202 and 4204 are 5rows wide and, as such, are only able to move totes into a destinationrow which is exactly 5 rows away from the source row. It should be notedthat the 5-row-wide mobile conveyers are exemplary in nature only andthat the invention is not intended to be limited to mobile conveyers 5rows in width. In the first step of the scenario, shown in FIG. 42(A),mobile carriers 4204 and 4204 are positioned at opposite ends of rows 2and 6 such as to be able to move totes between rows 2 and 6. Once mobilecarriers 4202 and 4204 are in place, the scenario operates verysimilarly to the embodiment previously described having fixed conveyers3700. As such, the series of steps to extract tote-of-interest E6 fromrow 6 will not be repeated here.

FIG. 42(B) shows the end of the scenario wherein tote E6 is on mobileconveyer 4202, while carrier 4204 is in the process of storing totes T2,S2, R2 and Q2, which have been pushed out of row 2, into row 6, as inthe previous scenario. Because the mobile conveyers also act as mobilecarriers, mobile conveyer 4202 is proceeding to an exit point of thesystem to drop off tote E6. FIG. 42(C) shows mobile conveyer 4202delivering tote E6 to the exit point of the storage structure.

It should be noted that it is possible, in the improved-efficiencyembodiments of the invention, to move the totes using both the“circular” and the “serpentine” methods described previously together.

To move the rows at a constant velocity, the improved-efficiency storagestructure may, in some embodiments, be provided with a drive mechanism.In some embodiments, the drive mechanism may comprise a rack and piniondrive wherein each tote may be configured with a rack and wherein thedriven pinions are disposed within the rows of the storage structure.The rows of totes are thereby able to be moved within each row in eitherdirection by driving the pinion gears against the racks on the totes. Insome embodiments, the mobile carriers may be provided with a motorizeddrive mechanism to drive the pinion gears in the row. In otherembodiments, each row may be provided with a motorized drive. In someembodiments, the drive mechanism on the mobile carriers may be a rackand pinion system as described above with respect to the rows of thestorage structure. In yet other embodiments, both the mobile carriersand the rows may be provided with a motorized drive mechanism such as tobe able to move one or more totes either from a conveyer and into adestination row or from a source row onto a conveyer as the row moves ata constant velocity. In yet other embodiments of the invention, otherdrive mechanisms may be used to move the rows in either direction. Inthe improved efficiency embodiments, an additional guiding mechanismcould be installed to keep the rack and pinion engaged and to preventthe totes from jumping the gears due to the insufficient weight of thetotes.

In a preferred embodiment of the invention, to avoid the cost ofinstalling drive motors within each row of the storage structure, mobilecarriers may be fitted with a powered drive mechanism and may transferpowered drive motion to a row. FIG. 43 shows various embodiments of sucha mechanism. In a first embodiment, as shown in FIG. 43(A), each mobilecarrier will be provided with two sets of pinion gears 4302 a, 4302 b,wherein the pinion gears of each set are joined by an axle. The two setsof pinion gears may be joined by a belt 3706 which engages gearing 4304on the axle to move each set of pinion gears in lockstep. As such, onlyone set of pinion gears 4302 a, 4302 b, needs to be driven by a motor(not shown) and the rotational motion of the driven set of pinion gearswill transfer to the un-driven set of pinion gears via belt 4306. Belt4306 may be any mechanism suitable for transferring the rotational memomotion of one set of pinion gears to the other set of pinion gears, forexample, a chain. In other embodiments, pinion gears 4302 a, 4302 b maybe driven independently by separate motors. Each mobile carrier is alsoprovided with a set of transfer gears 4304 which may be rotated aroundthe axle of pinion gears 4302 b.

FIG. 43(B) shows one row 4300 of the storage structure provided with asimilar mechanism as is present on the mobile carrier. The mechanismcomprises two sets of pinion gears 4310 a, 4310 b, joined by belt 4312which engages a gear on each axle such as to rotate the two sets ofpinion gears in lockstep. In other aspects of the invention, belt 4312may be any means of coupling pinion gears 4310 a, 4310 b, for example, abelt, a chain. A driveshaft, a gear train, etc. The two sets of piniongears 4310 a, 4310 b, are rotatably attached to storage structure 4300,and are un-driven. When the transfer gears 4304 present on a mobilecarrier are actuated by actuating rods 4308, they are rotated such as toengage set of pinion gears 4302 b on the mobile carrier with set ofpinion gears 4310 a in row 4300. In this embodiment, transfer gears 4304engage with axle gear 4307 on the mobile carrier and axle gear 4309 inthe row to drive the pinion gears 4310 a, however, other arrangements oftransfer gears and points of contact with the pinion gears are possible.The movement of transfer gear 4304 is shown in a disengaged position inFIG. 43(E), an intermediate position between a disengaged position andan engaged position in FIG. 43(F) and in an engaged position in FIG.43(G). As the pinion gears on the mobile carrier are driven by the motor(not shown), the presence of transfer gear 4304 will also cause the setsof pinion gears 4310 a, 4310 b in row 4300 to rotate in lockstep withthe set of pinion gears 4302 a, 4302 b on the mobile carrier.

As shown in FIG. 43(D), each tote 4301 may be configured with a set ofracks 4313 on a bottom surface thereof which may engage with piniongears in pinion gear sets 4310 a, 4310 b. As such, the tote 4301 whichis engaged by sets of pinion gears 4310 a, 4310 b, as well as any totesin the row coupled to it, may be moved in either direction by the drivemotor (not shown) located on the mobile carrier, thereby eliminating theneed for each row to be fitted with a separate drive motor. Oncetransfer gears 4304 are disengaged from sets of pinion gears 4302 b,4310 a by actuating rods 4308, the mobile carrier may be free to moveaway from row 4300 to another row in the storage structure. It should benoted that the actual configuration of the mechanism described as thepreferred embodiment may be varied and still be within the scope of theinvention. The novel aspect of the drive mechanism is that a motorlocated on the mobile carrier is able to transfer motion to a portion ofthe drive mechanism located within row 4300 to cause the movement of therow of totes in either direction. To minimize the probability of therack and pinion becoming disengaged (e.g. by popping off the track), thetop of tote 4301 could be prevented from moving up by passiverollers/skids that prevent the totes from jumping off the gears.

Note that, in the event that mobile carriers are disposed on both sidesof a full row, such as the situation wherein one mobile carrier ispushing a tote into a row and the other mobile carrier is disposed onthe opposite side of the row to receive a tote which is being pushed outof the row, the pushing and pulling motions of the mobile carriers willneed to be coordinated.

FIG. 43(H) is a second possible embodiment of the invention wherein themobile carrier is fitted with a powered drive mechanism to transferpowered drive motion to the row. In this embodiment, mobile carriers3710 is fitted with a gear 4305 driven by a motor. Gear 4305 in similaror identical to gear 4304 shown in FIG. 43(A). When mobile carriers 3710adjacent a row, gear 4305 may rotate into contact with pinion gears 4310a, located within the row. In one embodiment, rotational power may betransferred from pinion gear 4310 a to pinion gear 4310 b via belt 4312.As with the previous embodiment, tote 4301 is fitted with a rack 4313 ona surface thereof to interface with pinion gears 4310 a, 4310 b. Eachrow may also be fitted with one or more mechanical guides 4350 to allowthe totes to move along the longitudinal axis of the row and to maintainproper engagement of the pinion gears 4310 a, 4310 b to the rack 4313.Mechanical guides 4350 may be configured with rollers guide rollers 4352or other means of reducing friction between the totes and the storagestructure as the rows of totes are moved. In this embodiment, the drivepinions 4310 a, 4310 b that contact the tote rack 4313 are only in thestorage structure, while the powered drive pinion is still on the mobilecarrier 3710.

FIGS. 44 (A-J) illustrate yet another embodiment of the invention inwhich the layers are vertically-oriented instead ofhorizontally-oriented. In this embodiment, the totes are arranged inrows that are in the same vertical column. There can be one or more rowsbetween the source row (i.e., the row from which totes are retrieved)and the destination row (i.e., the row into which totes are stored). Oneadvantage of the vertically-oriented rows is that totes may be movedfrom a higher row to the lower row with the assistance of gravity.

FIG. 44(A) is a side view of three vertically-oriented rows of toteswherein the tote-of-interest is tote C3. In FIG. 44(A), tote-of-interestC3 is the third tote from the end in the row “C”.

FIG. 44(B) shows the row “C” being moved to the left such that tote C1is now outside of the storage structure.

FIG. 44(C) shows that once tote C1 is outside of the storage structure,tote C1 is moved downward from row “C” toward row “A”. Because thismotion is in the direction of gravity, it requires less energy to movethe tote from row “C” to row “A”. The downward motion of the totes fromrow “C” to row “A” may be assisted to ensure proper deceleration orvelocity or can be unassisted using only gravity. In preferredembodiments of the invention, the storage structure may be configuredwith a conveyer or some other mechanism on the left side of thevertically-oriented rows for guiding the tote as it falls from row “C”to row “A” and for slowing and stopping the tote when it is aligned withrow “A”. As tote C1 moves away from row “C”, it is automaticallydecoupled from tote C2. As such, in this embodiment, the rows can stillmaintain a constant velocity as totes are moved into and out of thestorage structure and decoupled from or coupled to their rows.

FIG. 44(D) shows that, as tote C1 approaches the row “A”, the downwardmotion of tote C1 is slowed and its downward velocity is reduced tozero. As tote C1 moves to the same height as row “A”, it can beautomatically coupled to tote A1 in row “A”.

In FIG. 44(E), tote C1 is pushed into the left side of row “A”, whichthen causes tote A4 to be pushed out of the right side of row “A”.Similarly, tote C2 is moved out of the row “C”. In the position shown inFIG. 40(E), the totes in row “C” are coupled to tote C2 so they aremoved along with tote C2. In addition, tote C1 and A4 are coupled to theother totes in row “A” so they are moved along with these other totes.

FIG. 44(F) shows tote C2 being lowered from row “C” towards row “A”assisted by gravity. As tote C2 moves away from row “C”, it isautomatically decoupled from tote-of-interest C3. Simultaneously, toteA4 is raised toward row “C”, but because it is not in the direction ofgravity, it requires a lifting motion through other power/motionsources. In some embodiments, the totes on the right-hand side of thevertically-oriented rows may be raised using a conveyer, a mobilecarrier or some other mechanism to elevate the tote to its destinationrow.

FIG. 44(G) shows tote C2 now aligned with row “A” and becomes coupled totote C1. In addition, tote A1 has been raised to row “C” and is ready tobe pushed into the row.

FIG. 44(H) shows several actions. First, the tote-of-interest, C3, ismoved out of row “C”. Because tote-of-interest C3 is coupled to tote C4,tote C4 moves to the left. Second, tote A4 is pushed into row “C”. Notethat, because there is a gap between tote C4 and tote A4, tote A4 doesnot become coupled to the other totes in row “C”. Lastly, tote C2 ispushed into destination row “A” thereby pushing tote A3 out of row “A”.

In FIG. 44(I), tote-of-interest C3 has been lowered to the level of row“A” using the gravity-assist, while tote A3 has been raised to the levelof row “C” by the conveyer (not shown) on the right side of thevertically-oriented rows.

Finally, FIG. 44(J) shows tote-of-interest C3 being lowered below row“A”, and, eventually, to an exit point of the storage system.

Software Architecture

FIG. 45 shows one implementation of a software architecture to manageand optimize the storage and retrieval processes used to store andretrieve totes within this system. A warehouse execution system (WES)4500 provides both a desired queue for totes to be stored and a desiredqueue for totes to be retrieved. Each of these queues are processed intothe tote placement algorithms 4502. These algorithms optimize andre-order the queues based on several factors that include, but are notlimited to, maximum movement efficiency of the robotic carriers andoptimal placemen/storage of totes within the storage structure. Toteplacement algorithms 4502 provide the robotic system controller thedesired row(s) to place and/or retrieve a tote from. This information isused by the robotic system controller 4504 to determine motion paths andexecute the tote storage and retrieval process.

The state of the totes within storage structure is also monitored by therobotic system controller 4504 which updates both the storage state oftote locations and the autonomous carrier state locations and contentsback into tote placement algorithms so that it can continue to updatecarrier motion and tote placement/storage locations for maximumefficiency. Additionally, the robotic system controller 4504 sendsoperational information back to the WES 4400 to give estimates onstorage and retrieval times and confirmation of tote storage andretrieval so that the queues are properly updated.

This software system could include optimizations that include, but arenot limited to, deciding which totes should be prioritized for retrievalin the system, the optimal stocking placement for products based oneither priority or by how often the product is required to be retrievedfrom the system, planning for optimal placement of totes being stored inthe system, and for how to manage “holes or gaps” in the system thatresult from a tote being retrieved from the system for other operations.It is important to note that there could only be a single gap on anyrow.

An alternate embodiment of the software architecture is shown in FIG. 46. A warehouse management system (WMS) 4600 monitors and updates awarehouse's inventory database 4602 based on delivery schedules, orders,and service level agreements (SLA)s. The WMS 4600 communicates withcarrier traffic and safety controller 4604 for the automated carriers aswell as all of the external transport systems for totes (conveyers,lifts, pick stations, loading stations, etc). The external totetransport 4606 is able to handle the material flow of deliveries cominginto the system as well as fulfilled orders going out of the system. Theexternal tote transport control 4608 is able to handoff control of thetote transport to the carrier traffic and safety controller 4604 whentotes are flowing into or out of the storage structure. The handoffcontroller 4610 is able to assign the totes that are being placed orretrieved into the system to a particular set of carriers 4612, eachwith their own carrier controller 4614 that consists of communications,motion control, and tote manipulation logic controller. As the carriereither stores or retrieves the tote, it continually updates its locationvia on board localization 4616 and is able to execute desired operationsvia on on-board low-level controller 4518. As the carriers execute theirprocesses, they communicate with the carrier traffic and safetycontroller which updates the required trajectories and motions based onthe top-level motion requirements for the system.

In preferred embodiments, the hardware components of the system arecontrolled via software executing on one or more processors. Thesoftware may be stored on a non-transitory computer-readable storagemedium. In various embodiments of the invention, a process, a system anda non-transitory computer-readable storage medium containing thesoftware may be claimed.

In addition to the components described herein, a means of communicatingthe instructions to and receiving status from each of the carriers aswell as a means of sending instructions to and receiving status fromeach of the input/output mechanisms will be necessary. These interfaces,in preferred embodiments, will be wireless to avoid the entanglement ofwired connections as carriers move about the carrier support structures.

In addition, various embodiments of the invention will require adatabase to store the current location of each tote stored within thestorage system. The locations, in various embodiments, may include alayer indicator indicating the layer in the storage system in which eachtote is stored, a row indicator indicating the row within the layer inwhich each tote is stored, and a depth indicator where within the roweach tote is stored.

The software may include various optimization routines which may useinformation in the database and the current status of the carriers inthe input/output mechanisms to optimize movement of the carriers and theorder in which the totes are stored and retrieved. In preferredembodiments of the invention, the system may be optimized to obtain theminimum time to retrieve any particular tote from the storage system or,in the alternative, to maximize the number of retrievals per unit timeof the system.

In some embodiments of the system, the totes may be provided with ameans of identification, for example, an RF tag or a barcode, which maybe read by a sensor in the system for confirming the location of a toteas it is moved into or out of the storage system.

In certain embodiments of the system, the totes are unidirectional innature. That is, the totes must be stored in a certain orientation inthe system to enable the coupling of the totes to other totes withineach row. As such, the system may be provided with a means for orientingtotes such they are oriented in the proper direction before they arestored, or, alternatively, for rejecting totes which are placed into thesystem in a non-conforming orientation.

The invention has been described in the context of specific embodiments,which are intended only as exemplars of the invention. As would berealized, many variations of the described embodiments are possible. Forexample, variations in the design, shape, size, location, function andoperation of various components, including both software and hardwarecomponents, would still be considered to be within the scope of theinvention, which is defined by the following claims.

We claim:
 1. A storage structure comprising: a plurality of layers, eachlayer comprising a plurality of rows for storing a plurality of totes;and a conveyer located on opposite ends of any layer; wherein totesstored in a source row may be removed from an end of the source row andonto a conveyer as the totes in the source row are moving at a constantvelocity toward the conveyer; and wherein totes on a conveyer may bestored in a destination row as the totes in the destination row aremoving at a constant velocity away from the conveyer.
 2. The storagestructure of claim 1 layer further comprising: one or more drivemechanisms for moving totes within a source or destination row at theconstant velocity toward either of the opposite ends of the layer. 3.The storage structure of claim 2 wherein the one or more drivemechanisms comprise a rack and pinion mechanism wherein each row of thestorage structure comprises one or more pinions and wherein each of thetotes is equipped with one or more racks.
 4. The storage structure ofclaim 3 further comprising: one or more mobile carriers located betweeneach conveyer and its respective side of the layer.
 5. The storagestructure of claim 1 wherein the conveyer also serves as a mobilecarrier.
 6. The storage structure of claim 4 wherein a motorized portionof the drive mechanism is built in to the one or more mobile carriers.7. The storage structure of claim 6 wherein the one or more drivemechanisms comprise: a motor; one or more transfer gears driven by themotor which engage one or more pinion gears in the storage structure totransfer driven rotational movement from the motor to the one or morepinions gears on the storage structure.
 8. The storage structure ofclaim 6 wherein the one or more drive mechanisms comprise: one or moredriven pinion gears located on the mobile carrier; a motor for drivingthe one or more driven pinion gears; one or more un-driven pinion gearsrotatably attached to a source or destination row of the storagestructure; and one or more transfer gears which engage the driven piniongears and the un-driven pinion gears such that the driven rotationalmovement of the driven pinion gears by the motor also serve to rotatethe one or more pinion gears within the source or destination row;wherein the one or more un-driven pinion gears located within the sourceor destination row engage one or more racks disposed on each of theplurality of totes such as to be able to move one or more of theplurality of totes in either direction within the source or destinationrows.
 9. The storage structure of claim 6 wherein: totes being removedfrom an end of the source row pass through a mobile carrier and onto aconveyer; and totes being stored in a destination row pass from aconveyer, through a mobile carrier and into the destination row.
 10. Thestorage structure of claim 9 wherein totes being removed from the sourcerow move in directions both parallel to the longitudinal axis of thesource row and perpendicular to the longitudinal axis of the source row,such as to move in an approximately circular path as the tote passesthrough the mobile carrier and onto the conveyer.
 11. The storagestructure of claim 10 wherein a tote moving from a source row isdecoupled from the source row as the tote moves through the mobilecarrier and onto the conveyer.
 12. The storage structure of claim 9wherein totes being moved from a conveyer to a destination row move indirections both parallel to the longitudinal axis of the destination rowand perpendicular to the longitudinal axis of the destination row suchas to move in an approximately circular path as the tote passes throughthe mobile carrier and into the destination row.
 13. The storagestructure of claim 12 wherein a tote moving into a destination row iscoupled to the destination row as the tote moves through the mobilecarrier and into the destination row.
 14. The storage structure of claim2 wherein the conveyers located at the opposite ends of any layer aremobile conveyers spanning the length of multiple rows.
 15. The storagestructure of claim 14 wherein totes being removed from the source rowmove in directions both parallel to the longitudinal axis of the sourcerow and perpendicular to the longitudinal axis of the source row, suchas to move in an approximately circular path as the tote moves from thesource row onto the mobile conveyer.
 16. The storage structure of claim14 wherein totes being moved from a mobile conveyer to a destination rowmove in directions both parallel to the longitudinal axis of thedestination row and perpendicular to the longitudinal axis of thedestination row such as to move in an approximately circular path as thetote passes from the mobile carrier and into the destination row. 17.The storage structure of claim 1 wherein the layers are orientedvertically.
 18. The storage structure of claim 17 wherein the movementof totes from a higher source row to a lower destination row is assistedby gravity.
 19. The storage structure of claim 17 wherein totes movedfrom a lower source row to a higher source row are lifted by a conveyer.20. A method for arranging and manipulating totes in a storage structurecomprising a plurality of layers, each layer comprising a plurality ofrows for storing a plurality of totes, the method comprising:positioning a first mobile carrier at an end of a source row; moving thetotes in the source row at a constant velocity toward a first conveyersuch that one or more totes are moved out of the source row and movethrough the first mobile carrier onto the first conveyer; positioning asecond mobile carrier at the end of a destination row; and moving thetotes in the destination row at a constant velocity away from the firstconveyer such as to accommodate one or more totes moved from the firstconveyer and through the second mobile carrier into the destination row;wherein the conveyer moves the one or more totes in a direction from thesource row to the destination row.
 21. The method of claim 20 furthercomprising: positioning a third mobile carrier at an opposite end of thedestination row from the second mobile carrier; and moving one or moretotes pushed from an opposite end of the destination row as thedestination row moves away from the first conveyer and toward a secondconveyer through the third mobile carrier and onto the second conveyer.22. The method of claim 21 further comprising: positioning a fourthmobile carrier between the second conveyer and another row in the layer;and moving the totes moved on to the second conveyer into the other rowthrough the fourth mobile carrier.
 23. The method of claim 22 whereinthe other row is the source row.
 24. The method of claim 23 wherein theother row is a row other than the source row.
 25. The method of claim 21wherein the first and second mobile carriers are the same carrier andwherein the third and fourth mobile carriers are the same carrier.
 26. Amethod for arranging and manipulating totes in a storage structurecomprising a plurality of layers, each layer comprising a plurality ofrows for storing a plurality of totes, the method comprising:positioning a first mobile conveyer at an end of any layer between asource row and a destination row; moving the totes in the source row ata constant velocity toward the first mobile conveyer such that one ormore totes are moved out of the source row and onto the first mobileconveyer; moving the totes in the destination row at a constant velocityaway from the first mobile conveyer such as to accommodate one or moretotes moved from the first mobile conveyer and into the destination row;wherein the conveyer moves the one or more totes in a direction from thesource row to the destination row.
 27. The method of claim 26 furthercomprising: positioning a second mobile conveyer at an opposite end ofthe layer between the destination row and another row; moving one ormore totes pushed from an opposite end of the destination row as thedestination row moves away from the first mobile conveyer and toward thesecond mobile conveyer onto the second mobile conveyer.
 28. The methodof claim 27 further comprising: moving one or more totes pushed onto thesecond mobile conveyer into the other row.
 29. The method of claim 28wherein the other row is the source row.
 30. The method of claim 28wherein the other row is a row other than the source row.